1. Field of the Invention
The invention relates to a routing method, and more particularly, to a network communication system, a software-defined network controller and a routing method thereof.
2. Description of Related Art
Software-defined network (SDN) is a network virtualization technology. SDN overturns the long-standing network architecture by changing control mode of traditional network architecture from distributed control into centralized control, so that network equipments tend to be more standardized and simplified. SDN becomes the focus of development in the next generation network technology since it not only can improve flexibility and performance in network operation, but also reduce operational management costs.
The main concept of the SDN technology is to adopt a generic “data flow table” for data exchange. The routing and exchanging information in the network may be expressed as a data flow to be stored into the data flow table. Each data flow entry in the data flow table may be used to describe forwarding policy, data operation, data state and the like.
A SDN network generally includes at least one network equipments (e.g., a SDN switch) and a SDN controller. The SDN controller is charge of a routing control for generating the data flow table according user's configuration or a dynamically operated protocol and transmitting the data flow table to the SDN switch. The SDN switch is in charge of a data forwarding based on the data flow table, and is configured to match and process packets according to the data flow table when receiving the data flow table from the SDN controller. In other words, the SDN controller can issue the data flow table to the SDN switch through a control channel, so as to achieve the data forwarding and realize separation of the data forwarding from the routing control.
With rapid development and increasing traffic of the Internet, accessing traffic of network-based data also shows a rapid growth, which is hard to be handled simply by using one single server. In order to provide a better service quality, services must be provided by deploying a large amount of service nodes for providing the same service. A load balancing technology may be used to spread the service traffic across different nodes for processing.
However, if a service chaining is further introduced to the nodes for providing the same service when the SDN controller adopts the centralized management, in order to achieve the load balancing during the service chaining of network traffic, chaining of the service nodes and establishment of routing paths thereof may result in an excessive setting for the data flow table entry. This means that the SDN controller has to store a massive amount of data flow table entries, which leads to overloading.
In other words, it is one of the most concerned issues for person skilled in the art as how to develop a method for the SDN controller to reduce the loading thereof during the service chaining in the SDN network.